Americans are getting so little sleep these days that the Centers for Disease Control and Prevention has declared insufficient sleep a public health epidemic. About a third of Americans are running on six or fewer hours of sleep each night when seven to eight hours is considered optimal. And that comes at a price: All of these lost hours of shut-eye have serious health implications—from weight gain to an increased risk of heart attack, along with a duller-looking complexion.Even though we spend about a third of our lives asleep, many of us pay little attention to our sleep routines. We don’t think twice about staying up well past our bedtimes to meet a deadline or watch a movie, and we check email right up until we turn off the lights. But good sleep hygiene plays a fundamental role in staying healthy and happy, not to mention awake for those morning meetings. Knowing how much sleep, and in particular, how much quality sleep, you’re actually getting is the first step to sleeping better—and thus, the trend of sleep trackers emerged.Scientists have been tracking how people sleep in labs for decades, but never has it been so easy to monitor your own sleep habits at home. From iPhone apps to headbands, sleep trackers are flooding the market. Some of the most popular sleep gadgets are the all-in-one wristbands from companies such as Basis, Fitbit and Jawbone. For under a couple hundred dollars, these watch-like monitors claim they will improve your overall health by studying your exercise levels and sleep routine.How Sleep Trackers WorkTechnically, sleep trackers and fitness trackers are wrist-sized accelerometers that measure the force of acceleration, whether caused by gravity or movement. The same technology is used to sense your golf swing by a Wii remote and to determine tilt and orientation of your phone. Accelerometers in fitness bands collect data on movement, which is then put into algorithms to determine activity levels or sleeping habits.“People are not usually good at estimating their sleep patterns, especially if they are inconsistent,” explains Julie Kientz, an assistant professor at the University of Washington who studies how technology can improve health. Wrist trackers allow you to keep tabs on your sleep—“better than you’d likely be able to do on your own”—especially over the long term, points out Kientz. Making people more self-aware is the first step to better sleep hygiene.Of course, sleep trackers aren’t perfect machines. Because they track movement, they can be tricked if you sit still too long. They’re also not generally good at sensing your sleep state, like the difference between light sleep, deep sleep and REM sleep. Nor are they diagnosticians. Diagnosing sleep apnea, for example, requires monitoring breathing and an EEG, or electroencephalography, which is a machine that detects electrical activity in the brain.There’s also the issue of effort. Some trackers require user input to work correctly, such as remembering to switch the tracker to sleep mode. Or, if you want to really get insights into what drives your sleeping patterns, you have to enter what you eat or drink into the accompanying app. Are you drinking caffeine too late at night? Have too much light in your bedroom? A fitness and sleep tracker can’t say, at least not without your help. “If we can develop a way of making sleep sensing to be completely unobtrusive and does not require the wearer to interact with it—or even to wear it!—without losing accuracy, then that would definitely improve their ability to use them long term,” notes Kientz. Still, she says that wrist models like the Jawbone Up or the Fitbit Force are “one of the best methods of estimating sleep patterns outside of a sleep lab.”Data alone, however, don’t mean much. “While trackers may allow people to identify that they have bad sleep habits,” says Kientz, “they do not necessarily help them determine why they have those habits and what they can do about it.” Or, as Andrew Rosenthal, product manager for Jawbone’s health platform, puts it: “Data are nice, but understanding is better.”Taking Trackers to the Next LevelJawbone and their fitness band Up have taken the leading role in the industry, seeking to go beyond data to actually improve behavior. “We’re really good at tracking,” says Rosenthal, “but that isn’t the question. The question is: Can we help people live better?”Rosenthal began his career as a scientist, working at the intersection between psychology and behavior. Though he considered the academic route, his real passion lies in helping people help themselves, so he transitioned into the business world seeking to connect health and technology. According to Rosenthal, Jawbone’s Up system is “more than a band.” “It’s data and science to lead to healthier behavior,” he says.Jawbone has invested heavily in data science, seeking to use the information they gather to learn about how people sleep. They analyzed data from more than 1,600 Up users and more than 5,000 nights of sleep over three months in 2013, and found that users lost an average of 37 minutes of sleep if they had their laptops in their rooms and 13 minutes of sleep if their cell phones were next to their beds.Data like these reveal simple behavioral changes that people can make to catch a few more zzz’s, but Rosenthal’s hope is to go beyond them. Jawbone’s newest app release contains personalized behavior-modifying notifications to motivate you to improve your daily habits based on your own data. The app’s “Today I Will” prompts challenge the user to meet a goal such as getting to bed earlier so you’re not exhausted in the morning. The app will also connect the fitness data to sleep patterns to show just how much of an impact nightly habits are having on daily activities. What’s more, Jawbone’s new “Up Coffee” app helps users track their caffeine consumption during the day and reveals how it’s impacting their sleep—no Up wristband required. “It’s not just the data,” says Rosenthal. “It’s the right data to the right person at the right time.”Although Kientz points out that many commercially available sleep trackers have not been validated through scientific studies, she and others are putting trackers, such as Fitbit, to the test—and the results are promising. So far, Jawbone’s gentle nudges appear to have a positive impact. Jawbone found that users who agreed to a “Today I Will” prompt encouraging them to get to bed a little earlier got 23 more minutes of sleep than those who brushed the alert aside.Ultimately, the key is interaction. While fitness trackers are requiring less and less input from the user, they still require interaction to work. All the data in the world won’t help you sleep better unless you use it to modify your behavior. What’s great about these products is that they allow you to easily collect and view information, and some, like Jawbone’s Up, are starting to analyze your data to give you personalized tips. Still, it’s up to you to take that information and use it wisely—and hopefully, prioritize getting a good night’s sleep.Spa Week is April 21-27! That means you can indulge in a slew of spa treatments for a wallet-friendly and guilt-free $50 a pop. Start booking your appointments at one of the 800 participating spas right now at the Spa Week website.